Competing nitrate reduction processes in coastal sediments

Supervisor: Beate Kraft

The global bioavailable nitrogen pool has more than doubled due to human activities like using fertilizers. About a quarter of the nitrogen that human activities have released into the environment ends up in coastal areas as nitrate, where it leads to eutrophication and algal blooms using different nitrate reduction processes either to dinitrogen gas, which is thus removed from the environment or to bioavailable ammonium, which may severe eutrophication. In this project, you will study which nitrate reduction process dominates in coastal sediments and the underlying controlling mechanisms.

 

Interspecies interactions in Baltic Sea sediments

Supervisor: Amelia Rotaru

Microorganisms do not live alone in the environment but rather interact with one another to gain energy for life. Recently, we discovered a new type of interaction between bacteria and archaea, which requires electrically conductive connections between cells. These connections could be established either by self-built conductive molecules at the cell surfaces or by conductive particles from their natural environment. Conductive particles have been shown to accelerate interspecies associations between certain bacteria and archaea. One such conductive particle is magnetite - an iron oxide abundant in marine environments and released by rock erosion due to climate change. Your M.Sc. thesis will involve hunting for electric interactions in marine sediments, and you will ascertain whether minerals released by rock erosion stimulate such interactions and global methane emissions. Such electric interactions could be a new source of methane in marine environments. Your research will tackle our understanding of the global iron and methane cycles and the possible role of these minerals in accelerating greenhouse gas emissions and global warming.